1. Field of the Invention
The present invention relates generally to injection molding and, more particularly, to a manifold assembly for injection molding.
2. Description of the Related Art
Injection molding is a widely known manufacturing process used to produce a variety of parts. Injection molding involves introducing a molten material, for example a molten plastic or resin, into a cavity within a mold until the cavity is filled. The molten material hardens in the mold in the shape of inner surfaces of the cavity. After the molten material hardens or cures, the hardened or cured material is removed from the cavity.
For injection molding, a manifold assembly is typically used for conveying molten material from a central injection portion or sprue to a number of cavities or to multiple points within one large cavity of the mold. An example of such a manifold assembly is disclosed in U.S. Pat. No. 4,964,795 to Tooman. In that patent, a manifold assembly has an integral or one piece, cast, cylindrical manifold with a passageway and at least one nozzle extending outwardly from the manifold and having a passageway through which a molten material may pass. The terminal end of the passageway of the nozzle, called a gate, is in fluid communication with the cavity of the mold.
It is also known that the manifold assembly may be used to mold arcuate parts such as a wheel well liner for a motor vehicle. Typically, the manifold assembly has the nozzles orientated perpendicular to the manifold. As a result, a secondary operation is required or a shelf on the mold for the nozzle is required to mold an arcuate surface of the wheel well liner during the injection molding-process. In addition, a vestige is created on the molded arcuate surface due to the injection molding process, which can be up to two inches in length. As a result, secondary operation is required to remove the vestige.
Therefore, it is desirable to provide a manifold assembly that has nozzles that are tangential to an arcuate surface to be molded. It is also desirable to provide a manifold assembly for molding a wheel well liner while eliminating the need for a secondary operation for the molding process. It is further desirable to provide a manifold assembly for molding a wheel well liner that minimizes any vestige as a result of the molding process. Therefore, there is a need in the art to provide a manifold assembly that meets these desires.